With a carrier aggregation (CA) technology introduced in the 3rd Generation Partnership Project (3GPP), user equipment (UE) may use multiple component carriers (CC) simultaneously to perform uplink and/or downlink communication, which can improve a transmission rate and quality of service of a network, ensure rates of common users without significantly increasing configuration bandwidth, and provide a higher throughput for some users.
CCs in carrier aggregation are classified, according to functions carried in the CCs, into a primary cell (PCell) and a secondary cell (SCell). The PCell is a cell that works on a primary frequency band; UE performs an initial connection establishment process or starts a connection re-establishment process in the cell, and the cell is indicated as a primary cell during a cell handover process. The SCell is a cell that works on a secondary frequency band; once a radio resource control (RRC) connection is established, the secondary cell may be configured, to provide an extra radio resource for UE. If CA is not configured, UE in an RRC connected state has only one serving cell, that is, the PCell; if CA is configured, a serving cell set includes the PCell and the SCell. In addition, carriers corresponding to the Pcell and Scell may be carriers of a same base station or may be carriers of different base stations. For example, carriers corresponding to the Pcell and Scell may be carriers of a macro base station, or may be carriers of small cell (Small cell) base stations that are densely deployed in a hotspot area of a macro cell on the basis of a conventional macro base station cellular network to meet a rapidly growing traffic requirement. When carriers corresponding to the Pcell and Scell are carriers of different base stations, a small cell base station may indicate a carrier status of a carrier of the small cell base station to a macro base station by means of an ideal backhaul or a non-ideal backhaul.
After an initial security activation procedure, the SCell cell may be activated or deactivated by using an RRC connection reconfiguration message. When user equipment has relatively low traffic, some CCs may be released (that is, deactivated), so as to avoid a waste of carrier resources and electric quantity of the user equipment in CA.
In the prior art, a combination of a user equipment SCell carrier activation or deactivation mechanism, which is based on a Media Access Control element (MAC CE), and deactivation timers (Deactivation Timers) is provided. An SCell activation or deactivation operation based on a MAC CE is controlled by a base station, and user equipment may acquire activation information or deactivation information according to an activation indication received from the base station.
However, to implement real-time dynamic adjustment of a carrier, fast carrier selection (FCS) needs to be implemented during carrier activation or deactivation. However, in the prior art, when an activated state or a deactivated state of a carrier is indicated to user equipment by using a MAC CE, a transmission delay of MAC signaling can hardly meet a requirement of the FCS, and indicating the activated or deactivated state of the carrier of a base station to user equipments one by one occupies channel resources and increases network load, which further increases an activation delay or a deactivation delay of the carrier; therefore, efficiency of indicating an activated state or a deactivated state of a carrier is relatively low.